"European Union proposals pose a grave threat to Britain’s financial services industry, which employs nearly two million people, accounts for 10 per cent of GDP, and generates over £50 billion in tax receipts annually. Although there have undoubtedly been regulatory failures in recent years, future policy should primarily be decided by Britain, not the EU. There are nearly 50 proposals under consideration by the EU. The most troubling include a unilateral, EU-wide financial transactions tax which would inflict enormous damage on Britain’s economic interests, a ban on some short-selling and a European Central Bank proposal that transactions on euro-denominated financial products are only cleared in the eurozone. … It is imperative that the Government fights our corner by arguing either for a new EU protocol or a Britain-specific legal safeguard. Without strong action, the present drift seriously threatens both British jobs and Exchequer revenues."

As notable as the letter itself is the ideologically diverse collection of MPs, listed below:

Andrea Leadsom MP

Chris Heaton-Harris MP

George Eustice MP

Desmond Swayne MP

Sajid Javid MP

Nicholas Soames MP

Ben Gummer MP

Margot James MP

Nadhim Zahawi MP

Harriett Baldwin MP

Karen Bradley MP

James Gray MP

Amber Rudd MP

Anne-Marie Morris MP

Bernard Jenkin MP

Dominic Raab MP

Lord Trimble

Steve Brine MP

Lord Risby

Mike Weatherley MP

Geoffrey Clifton-Brown MP

Mark Garnier MP

Esther McVey MP

Caroline Dinenage MP

Andrew Bridgen MP

Michael Fallon MP

Matthew Hancock MP

David Ruffley MP

Lord Flight

Viscount Trenchard

Followers of these intra-party European matters will recognise the first three names as key members of the "Fresh Start" group of MPs, which seeks to renegotiate, rather than withdraw from the EU.

Desmond Swayne is the PPS to the Prime Minister (and Sajid Javid is PPS to George Osborne) – and so it is rare to see his name beneath a letter. Even more rare is a collection of loyal MPs – Swayne, Matthew Hancock, Michael Fallon, Nicholas Soames, signing the same letter as noted Eurosceptics like Dominic Raab and Bernard Jenkin.

Eurosceptic MPs tend to say simple opt-outs or guarantees of protecting the City are not good enough, and that it must be protected from the reach of the European Court.

The interesting question that arises from this letter is: how long can this coalition of MPs last?